How to Use Oil-Based Polyurethane Over Water-Based Polyurethane

Good preparation is the key

Recoating a water-based acrylic floor finish with oil-based polyurethane is not usually a problem, so long as the old finish is properly buffed and cleaned before applying the new finish.

By the DIY experts of The Family Handyman Magazine:November 2002

Begin with a screening

Flooring wholesalers and veteran floor finishers agree that you can recoat water-based poly with oil-based as long as the original coating has completely cured—generally 30 to 60 days. You'll have to lightly buff the old finish with a power
buffer to prepare it for the new polyurethane.

Rent a power buffer and buy a fine (150-grit) screen. Use a light touch to avoid cutting through the finish and into the
stained wood. Before applying the polyurethane, vacuum the floor thoroughly
and then wipe up the remaining dust with a cloth dampened with
mineral spirits.

Ventilate the area well and wear a respirator rated for organic fumes
(follow the label warnings on the polyurethane can) when applying the
finish. Stay off it overnight and give it a few days to cure before bringing
in furniture or laying rugs down (or they may stick permanently!).

Tools & Materials List

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

Dust mask

Rags

You'll also need a power buffer, sanding screens, and a respirator rated for organic fumes.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.